Connection systems for fluid connections are known in the state of art and are, for example, used in the fields of medicine and medical equipment. The connection systems are used in the fields of infusion, artificial nutrition, with syringes and injection equipment, in transfusion and in the supply or transfer of various flow media, and as injection equipment in the context of medical and pharmaceutical devices, which inter alia also comprise several components.
In medicine, among other things absolute safety in the handling of syringes, infusion tubes, cannulae etc. is of the utmost importance. For this reason, in medical technology, the Luer principle or Luer lock principle has prevailed vis-à-vis previously common connection systems. Luer lock is a standardised connection system for cannulae, syringes and infusion tubes in the medical field.
In this design, a seal is achieved by a conical construction of the connection components (the so-called Luer cone). The internal cone of one connection side is also referred to as “female”, and the external cone of the opposite side is referred to as “male”. The cone has a standard gradient of 6%.
If, for the purpose of securing or locking the connection against inadvertent disconnection, the cone is supplemented by a threaded nut or union nut with a thread, the system is referred to as a Luer lock. The simpler version without a screw thread on the syringe nozzle is referred to as a Luer connector, Luer adapter or Luer slip.
The Luer lock system ensures compatibility among various manufacturers and is internationally recongised. Worldwide, the Luer lock connection has established itself for reversible connections of syringes, cannulae, infusion tubes, spinal needles and the like. This represents a great advantage, in particular in the context of international aid and disaster operations.
At the same time, however, the universality of the system is associated with a dramatic disadvantage and with resulting dangers. Because of its universal standardisation the Luer lock connection has inherent possibilities for mix-ups because the system is compatible for vascular applications (veins and arteries) and for spinal or peridural applications(spiral cord), partly also for enteral applications (e.g. feeding tubes) and respiratory applications (airways). Thus this connection technique basically does not prevent, for example, medication that has to be injected venously from erroneously being applied spinally (into the spinal fluid). Unfortunately, several cases of such mix-ups with fatal consequences have occurred.
Apart from the above, from the point of view of process technology the manufacture of the threaded nut or the union nuts, as they are used, inter alia, in the Luer lock system, is relatively expensive, because for the internal thread of the nut during the manufacture in plastic injection moulding, a tool that can be rotated out or folded out needs to be used. This results in a significant increase in tool costs and increased manufacturing expenditure. The disadvantage is particularly significant if a plural number of such threads are provided on one component.